Dispersions of water soluble polymers in oil

ABSTRACT

Water soluble polymers dispersed in a water-in-oil emulsion are treated to reduce the water content thereof to provide a polymer dispersed in oil which is stable to coagulation or agglomeration during subsequent treatment. The composition can be chemically modified and/or made self dissolving in water by addition of surfactant without polymer agglomeration.

This is a division of application Ser. No. 613,231, filed 9-15-75, nowU.S. Pat. No. 4,052,353 which is a CIP of Ser. No. 429,548 filed 1-2-74,now abandoned.

This invention relates to finely divided water soluble polymersdispersed in oils. More particularly, the present invention relates tostabilization of water in oil emulsions having finely divided polymerdispersed therein and to subsequent treatment thereof and uses therefor.The invention further relates to the production of water solublecondensation polymers.

Water in oil emulsions having finely divided water soluble polymersdispersed therein are known in the art. The primary disadvantage of suchemulsions is that attempts to further treat such emulsions generallyresult in coagulation or agglomeration of the polymer whereby thepolymer does not remain finely divided and dispersed in the emulsion.

Thus, for example, attempts to add surfactants to such emulsions torender the emulsions self inverting, whereby the polymer can bedispersed in aqueous solutions, have generally not been successful as aresult of coagulation or agglomeration of the polymer. As a result, ingeneral, such emulsions are inverted into water by separately adding thesurfactant and emulsion to the water, which necessitates separateshipping and handling of two products.

In U.S. Pat. Nos. 3,624,019 and 3,734,873, it is indicated that it ispossible, in some cases, to prepare a self inverting water-in-oilemulsion having finely divided polymer and surfactant dispersed therein;however, such patents indicate that there are severe limitations in thatthe addition of the surfactants may tend to interact with the emulsifieror emulsion and destroy it prior to use thereof.

Accordingly, there is a need for water soluble polymers dispersed inoil, which are more stable.

It is further known in the art to chemically modify various polymers,such as for example, acrylamide polymers by hydrolysis,aminomethylation, etc. Numerous difficulties have been encountered, ineffecting such modifications, in particular modification of polymershaving high molecular weights, as a result of the viscous naturethereof. Such problems, include, pumping problems, problems in uniformmixing of reagents to produce uniform reaction; problems in transmittingheat without local overheating, etc.

Accordingly, there is a need for improved means of chemically modifyingvarious polymers.

It is also known in the art to produce condensation polymers; however,in order to mitigate the problems associated with the viscous nature ofthe reaction mixture, it is necessary to effect such polymerizations atlow polymer concentrations. In addition, in some cases, it may benecessary to limit the molecular weight of the polymer.

Accordingly, there is a need for improvements in the technique forproducing water soluble condensation polymers.

In accordance with one aspect of the present invention, there isprovided a self-dissolving composition of finely divided polymer andsurfactant dispersed in oil in which the water content of thecomposition is at a value at which the polymer remains finely dividedand dispersed in the oil.

In accordance with yet a further aspect of the present invention, a selfdissolving composition of finely divided water soluble polymer dispersedin oil is produced by providing a water in oil emulsion having finelydivided water soluble polymer dispersed therein, reducing the watercontent of the emulsion to a value at which the polymer remains finelydivided and dispersed in the oil upon addition of a surfactant to renderthe composition self dissolving.

In yet another aspect of the present invention, a water soluble polymeris chemically modified by forming a water in oil emulsion having finelydivided water soluble polymer dispersed therein, reducing the watercontent of the emulsion to a value at which the polymer remains finelydivided and dispersed in the oil during the chemical modification andchemically modifying the polymer.

In still a further aspect of the present invention, a water solublecondensation polymer is produced by effecting condensationpolymerization of monomers in a water in oil emulsion.

In yet another aspect of the present invention, an acrylamide polymer ishydrolyzed by the use of ammonia.

The polymers used in the present invention are any one of the widevariety of water soluble vinyl addition polymers or water solublecondensation polymers. The term "water soluble" means that the polymeris soluble in water in an amount of at least 1%, , by weight.

Water soluble vinyl addition polymers are well known in the art, andsuch polymers are preferably used in producing the self dissolvingcompositions in accordance with the present invention. The mostpreferred vinyl addition polymers are polymers (the term polymer as usedherein refers to both homopolymers and copolymers containing two or moremonomeric units) of acrylamides, such as polyacrylamide and copolymersof acrylamide with acrylic acid or salts thereof which contain from 5 to95 weight percent of acrylamide. Also suitable are copolymers ofacrylamide with maleic anhydride, vinyl benzene, acrylonitrile, styrene,methacrylamide, etc.

As representative examples of other suitable water soluble vinyladdition polymers, there may be mentioned water soluble polymers ofacrylic acid, vinyl pyridines, vinyl benzyl dimethyl ammonium chloride,methacrylamide, sulfonates of acrylic esters, such as 2-sulfoethylacrylate, styrene sulfonates, quaternary or amino substituted acrylicand methacrylic esters, such as 2-aminoethyl methacrylate, and the like.

As representative examples of water soluble condensation polymers whichare useful in preparing the emulsions of the present invention or whichcan be prepared by the emulsion technique of the present invention,there may be mentioned, the polyamines, produced by condensation ofdifunctional amine with an epihalohydrin and/or alkyl dihalide.

The polymers used in preparing the emulsion of the present invention mayhave a molecular weight over a wide range; e.g., 10,000-25,000,000;however, the present invention is particularly applicable to highmolecular weight polymers; i.e., in excess of 100,000, in that suchpolymers are more difficult to subject to further treatment, such as bychemical modification and/or rendering same readily soluble in water.

The oils which are used in preparing the emulsions of the presentinvention may be any one of a wide variety of oils which do notadversely affect the polymer to be dispersed in the oil. The oil may beany one of a wide variety of liquids which are immiscible with waterincluding hydrocarbons and substituted hydrocarbons. As representativeexamples, there may be mentioned benzene, xylene, toluene, mineral oils,kerosenes, naphthas, chlorinated hydrocarbons, such asperchloroethylene, etc. A blend of organics can be used in preparing theoil phase. The oil phase preferably has a boiling point in excess of100° C to avoid excess loss of oil phase during water removal; however,lower boiling materials can be used, provided the oil phase isreplenished during water removal.

The water in oil emulsion having finely divided water soluble polymerdispersed therein may be prepared by any one of a wide variety ofprocedures, and is preferably prepared by the water in oil emulsionpolymerization technique for preparation of vinyl addition polymers. Inaccordance with such a procedure, a water in oil emulsion of watersoluble ethylenically unsaturated monomer(s) is formed and polymerizedunder free radical polymerization conditions to produce a latex of waterin oil emulsion having finely divided polymer dispersed therein. Arepresentative example of this technique is disclosed in U.S. Pat. No.3,284,393, hereby incorporated by reference.

Alternatively, and less preferred, the water in oil emulsions havingfinely divided water soluble polymer dispersed therein can be preparedby dispersing previously prepared polymer in a water in oil emulsion.Such techniques are known in the art and need not be set forth in detailfor a complete understanding of the present invention. In brief, suchtechniques involve comminuting the polymer to provide finely dividedpolymer (average particles size is generally less than 5 millimeter) andthen dispersing the polymer in a water in oil emulsion by means ofsuitable agitation. In most cases, a suitable oil soluble emulsifyingagent is used in preparing the emulsion. The emulsifier should be inertwith respect to the components present in the emulsion or used in thesubsequent treatment. In general, the better emulsifiers have HLBnumbers (Hydrophobic-liphophobic balance) of below 9 and preferablybelow 7.

The above techniques and other techniques for producing such emulsionsare known in the art and no further details are deemed necessary for acomplete understanding of the invention.

The water in oil emulsions having finely divided water soluble polymerdispersed therein, which are stabilized to polymer agglomeration, inaccordance with the present invention, generally contains from 50 to95%, by weight, water, and most generally from 60-80% water, based onpolymer and water. The amount of oil phase present in the emulsion isgenerally in the order of 25 to 75 weight percent, based on oil andwater phases.

In accordance with the present invention, the water in oil emulsionshaving finely divided water soluble polymer dispersed therein arestabilized with respect to agglomeration or coagulation of polymer topermit subsequent treatment thereof, by reducing the water contentthereof to a value at which the polymer remains finely divide anddispersed in the oil during subsequent treatment of the polymerdispersed in oil. It is to be understood that the term subsequenttreatment is intended to cover further chemical treatment of thedispersed polymer and/or addition of components to the polymer dispersedin oil, which without stabilization by water removal, would normallycause coagulation or agglomeration of the polymer particles.

In accordance with the present invention, the water content of thewater-polymer phase is reduced to less than about 40 percent, by weight,based on water and polymer. As should be apparent, the particularamounts of water which can be tolerated in order to provide the desiredstabilization will vary with the polymers employed and the type ofsubsequent treatment. In general, the water content of the polymer andwater phase is reduced to provide a water content in the order of 0 to40%, by weight, based on polymer and water. In most cases, the watercontent of the polymer and water phase is reduced to an amount of noless than 1%, by weight, based on polymer and water, in that completewater removal is not readily achieved. The water content is preferablyin the order of 1 to 30% and most preferably in the order of 1%, (insome cases 0%) to 15%, all by weight, based on polymer and water. Inaccordance with the aspect of the present invention wherein the polymeris to be further chemically modified, in most cases, the water contentshould be at least 5%, by weight, based on polymer and water, with theupper limits being as hereinabove described.

The selection of an optimum water content at which the polymer isstabilized with respect to agglomeration or coagulation duringsubsequent treatment is deemed to be within the scope of those skilledin the art from the teachings herein. It is noted, however, that lowerwater contents are required when using water soluble polymers containingsubstantial amounts of amines and/or emulsions which are to be storedover longer periods of time or stored at either high or lowtemperatures. Similarly, greater water removal is generally required forlower molecular weight polymers.

It is to be understood that in most cases, subsequent to the waterremoval step, the polymer is not present in the oil as an emulsion;i.e., the polymer is present as a suspension. It is to be understood,however, that the terminology that the water soluble polymer is finelydivided and dispersed in the oil is not intended to be limited bytechnical definitions of emulsions, suspensions, etc., in that thepresent invention is directed to compositions in which the polymerremains finely divided and dispersed in the oil during subsequenttreatment.

The water content of the emulsion is generally reduced by evaporation ofwater, preferably under vacuum. The evaporation is generally effected attemperatures from ambient to 100° C. The selection of an optimumtemperature is deemed to be within the scope of those skilled in the artfrom the teachings herein. Prior to or during the water evaporation,additional inert organic liquid may be added for the purpose of reducingviscosity and/or replacing oil distilled from the emulsion during waterremoval.

There are variations in the coagulating tendency of various latices andthe more sensitive the latex, the lower should be the temperature atwhich evaporation of water is carried out. Preferably below 100° andmost preferably below 70°.

As water is progressively removed, the temperature of evaporation may beraised higher without coagulation. For example, a preferred method ofoperation on a polymer may be to start at 40° C and go to 80° asevaporation procedes.

In accordance with the present invention, the hereinabove describedtechnique may also be used for providing the polymers as finely dividedsolids, by evaporating both water and oil. Applicant has found thatfinely divided polymer can be recovered, without adverse agglomerationor coagulation, by evaporating water and oil, thereby providing a simpletechnique for recovering the solid polymer produced by a water in oilemulsion polymerization technique.

As hereinabove noted, in accordance with one aspect of the presentinvention, the dispersion of water soluble polymer in oil having areduced water content, which renders the composition susceptible tofurther treatment without polymer coagulation, is subsequently treatedby the addition of surfactant to provide a self dissolving composition.It has been surprisingly found that any one of the wide variety of wellknown surfactants which would normally cause coagulation of the polymerdispersed in a water in oil emulsion, can be added to the composition ofthe present invention of polymer dispersed in oil of reduced watercontent, as hereinabove described, without effecting coagulation oragglomeration of the polymer. The surfactant added to the composition torender same self dissolving may be selected from any one of a widevariety of water soluble cationic, anionic or non-ionic surfactantsknown in the art. As known in the art, anionic surfactants includealkali metal, ammonium and amine soaps; salts of various sulfonic acids,sulfonated oils, etc.

Cationic surfactants include various long chain amines, quaternarysalts, etc.

Non-ionic surfactants include condensation products of various alcohols,phenols and amides with ethylene oxide; polyethylene glycol esters, etc.

The surfactants are well known in the art and examples of suchsurfactants are disclosed in U.S. Pat. No. 3,624,019.

It has been found that in order to be effective the HLB of thesurfactant should be above 8. In any case, the following relationshipshould obtain:

The resultant HLB of the following calculation should be preferablybetween ##EQU1## 8 and 18 and most preferably between 10 and 14.

The self dissolving compositions of the present invention includessurfactant in an amount to render the polymer self dissolving in water.In general, the compositions contain from about 0.1 to about 20%,preferably from 1 to 15%, by weight, of surfactant based on oil. Thewater content is as hereinabove described, whereby the polymer is finelydivided and dispersed in the oil after addition of the surfactant. It isto be understood that the present invention is not limited to suchillustrative amounts of surfactant, and the determination of suitableamounts is deemed to be within the scope of those skilled in the artfrom the teachings herein. In general, the polymer is present in the oilin an amount from 5 to about 90%, preferably 25 to 75%, all by weight.

The self dissolving compositions of the present invention are preferablyformed from water soluble ethylenically unsaturated addition polymers,and most preferably from polymers of acrylamides. The polymer is readilyreleased into water from the composition by adding the self dissolvingcomposition to water.

It is to be understood that additives other than surfactants can beadded to the self inverting composition, without effecting coagulationor agglomeration of the polymer. Thus, for example, in using the selfdissolving compositions for water treatment purposes, it may bedesirable to also add to the composition a biocide and or corrosioninhibitor, etc., and such additives can be added with the surfactant.The self dissolving compositions of the present invention areparticularly suitable for use in water treatment compositions in amanner known in the art.

As hereinabove noted, in accordance with another aspect of the presentinvention, the composition of water soluble polymer dispersed in oilhaving a reduced water content can be subsequently treated, in thedispersed phase, to chemically modify the polymer, without coagulationor agglomeration of the polymer.

The present invention is particularly applicable to the followingchemical modification of polymers of acrylamide and methacrylamide:

Hydrolysis of amide to carboxyl.

Dialkylaminomethylation of amide groups.

Sulfomethylation of amide.

Hoffman reaction with chlorine or bromine and base.

Exchange of amide nitrogen for nitrogen of N,N dimethylaminopropylamine.

The present invention is also applicable to the quaternization of aminecontaining polymers, and the alkylation of amines by halogen containingpolymers, in particular, acrylamide copolymers in which the comonomercontains an amino or halo group, respectively. Thus, for example, acopolymer of acrylamide and dimethylaminoethyl methacrylate can bequaternized with methyl chloride or a copolymer of acrylamide withchloroethylmethacrylate can be quaternized with trimethylamine dispersedin oil and having a reduced water content.

The finely divided low water content polymer, dispersed in oil,(prepared as hereinabove described by either forming an emulsion byadding polymer to a water in oil emulsion or producing the polymer bypolymerization in a water in oil emulsion; followed by reduction of thewater content) has an average particle size generally in the order of0.1 micron to 500 microns, and most frequently, 0.5 to 100 microns.Larger particle sizes could be used, but some of the advantages of theinvention are decreased.

The chemical modifications can be effected by using the reagents andconditions generally known in the art, except that the polymer istreated dispersed in oil, with the water content of the polymer being ashereinabove described. Solid reagent employed in the chemicalmodification may be added as fine powders, aqueous solutions orpre-emulsified in the same manner as the latex. In some cases,pre-emulsification of the reagent may be required in order to preventcoagulation or agglomeration of the polymer. Liquid reagents can also bepre-emulsified.

The acrylamide polymer, as hereinabove noted, may be chemically modifiedwith various known reagents, including, as representative examples,bases, dialkylamine and formaldehyde, sodium bisulfite and formaldehyde;N,N-dialkyldiamines, etc.

The chemical modification of acrylamide polymers may be effected atreaction temperatures known in the art, generally in the order of 15° to130° C at atmospheric or elevated pressures. The above conditions areonly illustrative, and the selection of suitable conditions is deemed tobe within the scope of those skilled in the art.

In accordance with the present invention, it has been found thatchemical modification of acrylamide polymers dispersed in oil, byhydrolysis can be effected with a suitable base, such as potassiumhydroxide, sodium hydroxide or ammonia. The hydrolysis is generallyeffected at temperatures of 20° C to 130° C, preferably at a temperatureof 50° to 100° C. It is to be understood that the present invention isnot limited to such illustrative temperatures.

It has also been found in accordance with the present invention, thatadvantageous results are obtained by the use of ammonia or ammoniumhydroxide, instead of other conventional bases, for the hydrolysis ofacrylamide polymers, in particular, those having a molecular weight ofat least 100,000. Thus, for example, improvement in neutralization ofacrylamide polymers in aqueous media are obtained by the use of ammoniaor ammonium hydroxide as a result of the ability to control hydrolysismore effectively.

In accordance with still another aspect of the present invention, watersoluble condensation polymers, in particular, polyamines, are producedby polymerization in a water in oil emulsion. By proceeding in thismanner, concentration of the polymer in the water phase can be increasedto concentrations greater than those heretofore used in the art, withoutthe disadvantages which would normally result from the presence of highpolymer concentrations.

As known in the art, polyamines are produced by condensation of apolyfunctional amine; i.e., an amine capable of at least doublealkylation, with an epihalohydrin or an alkyl dihalide.

As representative examples of suitable amines for the present invention,there may be mentioned: Methylamine, dimethylamine, ethylamine,ethanolamine, propylamine, N,N-dimethylethylenediamine,tetramethylethylenediamine, piperazine, ammonia, ethylenediamine,N-methylethylenediamine, the polyalkylenepolyamines includingdiethylenetriamine, tetraethylenepentamine and the correspondingpolypropylenepolyamines, p-phenylenediamine, p,p'-disaniline, and1,3-diamino-2-propanol and aniline are suitable. The amines need notpossess great water solubility, and the suitability of any particularamine as a raw material can be readily determined by laboratory trial.Mixtures of two or more bifunctional amines may be used.

The epihalohydrin used in this invention has the essential group##STR1## wherein the epoxy group is bonded to two carbon atoms, one ofwhich is bonded adjacently to a carbon atom having the halogen bondedthereto. The halogen is preferably chlorine for reasons of availabilityand cost, but may be bromine or iodine. The indicated free valences onthe carbon atoms are satisfied by hydrogen or lower alkyl groups,preferably the methyl or ethyl groups.

The epihalohydrin is preferably epichlorohydrin but may beepibromohydrin, epiiodohydrine, or one of the higher molecular weightvicinal halohydrins such as 3-chloro-1,2-epoxybutane,3-chloro-1,2-epoxypentane, etc. Diepoxides such as butadiene diepoxidemay also be used.

The alkyl dihalide used in the invention is preferably a dichloride ordibromine of lower alkanes (2-6 carbon atoms), with the halo groupspreferably being on the terminal carbon atoms. As representativeexamples of suitable compounds, there may be mentioned:1,2-dichloroethane, 1,2-dibromoethane, 1,3-dichloropropane,1,3-dibromopropane, etc.

The selection of suitable amines for condensation with a dihaloalkaneand/or epihalohydrin is deemed to be within the scope of those skilledin the art from the teachings herein.

The reaction is generally effected at temperatures known in the arti.e., temperatures in the order of 0°-100° C. In addition, the reactionmixture, as known in the art, preferably includes an acid acceptor; inparticular, an alkali metal hydroxide.

The general conditions for producing polyamine condensation polymers areknown in the art, and such teachings are applicable to the presentinvention.

In accordance with the present invention, the monomers are condensed ina water in oil emulsion, with the water phase, including monomer,generally comprising from 25 to 75%, by weight, of the emulsion, basedon water and oil.

The water phase is present in an amount to provide a polymer water phasecomprised of from 40 to 95%, of water, preferably 60 to 90%, all byweight, based on polymer and water. Subsequent to completion of thepolymerization, water may be removed, as hereinabove described toprovide more concentrated polymer in water solutions. The oil may alsobe removed, as hereinabove described to provide flowable composition ofpolymers of concentrations higher than heretofore available in the art.Thus, for example, the oil content could be reduced to the order of 10to 80%, preferably 15 to 70%, and most preferably 20 to 50%, of thetotal composition, by weight, which provides an improvement over the 10%polyamine solutions generally available in the art.

The monomers are emulsified in the oil phase by the use of a suitablewater in oil emulsifying agent. The emulsifier is generally present inan amount of from 0.1 to 10 percent, by weight, of the oil phase. Theemulsifiers are well known in the art and no further details are deemednecessary in this respect for a complete understanding of the invention.

It is also to be understood that the polyamine could be produced byconventional techniques, followed by emulsification of the water polymersolution in oil and evaporation of the water to produce a moreconcentrated aqueous solution of polyamine.

The invention will be further described with respect to the followingexamples, but it is to be understood that the scope of the invention isnot to be limited thereby.

EXAMPLE I

An acrylamide polymer known as Nalco 7171 is a high molecular weightpolymer of the type described in U.S. Pat. No. 3,284,393, Vanderhoff. Itis an emulsion comprising a continuous phase of hydrocrbon in which aresuspended fine particles of poly acrylamide gel. The composition ofNalco 7171 is approximately as follows:

    ______________________________________                                                          % by weight                                                 ______________________________________                                        Copolymer           30                                                        Water               33                                                        Hydrocarbon         28                                                        Emulsifier           4                                                        ______________________________________                                    

A 20 gram sample of Nalco 7171 was weighed into a 2 ounce bottlefollowed by 4.3 grams of toluene. The bottle was then connected to awater aspirator and vacuum was applied. The bottle was held at 20°-25° Cwith a water bath for 12 minutes, after which the temperature of thebath was raised to 40° C for 30 minutes and to 50° C for another 10minutes. The bottle was disconnected and the product was found to weigh13.7 grams (loss of 10.6 grams of water and hydrocarbon combined). Asample of the product was removed and designated Sample A. To theremainder of the product in the bottle (8.4 grams) was added 4.3 gramsof toluene. Vacuum was then applied over a 20 minute period while thebath temperature was raised from 25° C to 80° C. Distillation wasdiscontinued at this time and the remaining product was found to weigh6.1 grams. The product was diluted with 3 ml of VM & P naphtha anddesignated Sample B.

Samples A and B and a sample of untreated Nalco 7171 were subjected to acompatibility test with surfactant that was supplied along with thesample of Nalco 7171. The surfactant had the designation "Activator" andis a nonionic surfactant of the polyethylene oxide condensate type. Thecompatibility test consisted of adding 2 ml of sample to a vial followedby 0.08 ml of activator and then mixing. The samples were then observedover a two month period. The results were as follows:

    ______________________________________                                        Material          Appearance                                                  ______________________________________                                        Original Nalco 7171                                                                             Coagulation in two                                                            minutes                                                     Sample A          Coagulation in seven                                                          minutes                                                     Sample B          No coagulation observed                                                       over a two month inspec-                                                      tion period                                                 ______________________________________                                    

EXAMPLE 2

Part A

A 500 gram portion of 10% polyacrylamide gel (0.703 monomer mole) isplaced in a jacketed sigma mixer. This polyacrylamide has an intrinsicviscosity of 12.6 measured in 1 normal NaCl at 25° C. Heat is applied tothe jacket to bring the polymer mass to 50° C and mixing is started. Thereaction mixture is buffered on the alkaline side by addition of 5 g. ofNa₂ HPO₄ .2H₂ O and 8 g. of Na₃ PO₄.10 H₂ O. This is followed by 14.2 g.of 37% formaldehyde solution (0.176 mole). The temperature is held at50° C with mixing for 80 minutes, after which 20 g. of a 40%dimethylamine solution (0.176 mole) is added and the temperature raisedto 75° C and held for 30 minutes. A sample of the aminomethylatedpolyacrylamide is dissolved in 1 normal NaCl for determination of itsintrinsic viscosity which is found to be 9.8.

Part B

A 30% polyacrylamide latex is prepared by the technique of Vanderhoffand found to have an intrinsic viscosity of 11.9. The composition of thelatex is as follows:

    ______________________________________                                                             %                                                        ______________________________________                                        Polyacrylamide         30                                                     Water                  38                                                     Paraffine Solvent (Isopar M)                                                                         28                                                     Brij 92 (polyoxyethylene (2) oleate)                                                                  4                                                     ______________________________________                                    

In a 500 ml three neck round bottom flask equipped with a stirrer isplaced 166.5 g. of the above latex (50 g. polyacrylamide, 0.703 monomermole). Stirring is started and the latex is heated to 50° C after whichan emulsion composed of the following is added:

    ______________________________________                                        Step 1                                                                                             Grams                                                    ______________________________________                                        Na.sub.2 HPO.sub.4 · 2H.sub.2 O                                                           1.5                                                      Na.sub.3 PO.sub.4 · 10H.sub.2 O                                                           3.0                                                      37% formaldehyde     14.2 (0.176 moles)                                       Water                15.0                                                     Isopar M             12.0                                                     Brij 92              1.4                                                      ______________________________________                                    

After 90 minutes at 50° C, 29.1 g. of the following emulsion is added:

    ______________________________________                                        Step 2                                                                                             Grams                                                    ______________________________________                                        40% dimethylamine    20 (0.176 mole)                                          Isopar M             8                                                        Brij 92              1.7                                                      ______________________________________                                    

The latex is then heated to 75° C for 30 minutes, after which a sampleis dissolved in 1 normal NaCl containing 0.04% Triton X-100 fordetermination of the intrinsic viscosity of the aminomethylatedpolyacrylamide, which is found to be 11.5.

EXAMPLE 3

A 20 g. sample of Nalco 7171 is given the same drying treatment asSample B in Example 1. Gaseous ammonia is passed in over the stirredmixture so as to create saturation. The ammonia is passed in over thestirred mixture so as to create saturation. The ammonia atmosphere isthen maintained over a 4-hour period with stirring at 85° C. The produceis then blown with air to remove ammonia vapor. A solution of thepolymer shows strongly anionic behavior.

EXAMPLE 4

Part A

A 5 g. sample of polyacrylamide (0.703 monomer mole) having a molecularweight of about 6 million is dissolved in water to give 5% solution.This solution is heated to 85° C and 2.26 g. of 37% NaOH was added(0.022 mole). The base is mixed into the viscous mass, the reactor isclosed, and the mixture is heated at 85° C for 6 hours.

Part B

This experiment is carried out as in Part A except that instead of NaOH,1.01 g. of 37% ammonia (0.022 mole) is used. The neutralized polymer hasimproved properties with respect to the polymer produced in Part A.

EXAMPLE 5

Polyacrylamide having a weight average molecular weight of 3 million ismade up as 3% solution containing 30 grams of polyacrylamide (0.4222monomer mole) and 970 grams of water. To this solution is added 3 gramsof Na₂ PO₄.2 H₂ O, 5 grams of Na₃ PO₄.10 H₂ O and 3.4 grams of 37%formaldehyde (0.042 mole). The reaction mixture is held at 45°-50° C for80 minutes, after which 4.8 grams of 40% dimethylamine solution (0.042mole) is added. The temperature is then raised to 75° C and held for 30minutes. The mixture is cooled and designated Product A.

An emulsion formed from 100 grams of Product A, 96 grams of Low OdorParaffin Solvent (Exxon) and 4 grams of Brij 92(polyoxyethylene(2)oleate) is placed in a 500 ml round bottom flask andattached to a rotary vacuum evaporator that is fitted with a dip tubethat can be used to feed or withdraw material from the evaporator.

Concentration is carried out at a pressure of 40 millimeters of mercuryover the temperature range of 40°-80° C. As the amount of water takenoverhead reaches approximately 80 ml the contents of the evaporator areremoved and emulsified with another 100 ml of Product A. The hydrocarbontaken overhead is separated and returned to the emulsion. The newemulsion is returned to the evaporator and the cycle is repeated untilall of Product A is concentrated to a stable latex containing

    ______________________________________                                                               Grams                                                  ______________________________________                                        Aminomethylated polyacrylamide                                                                         33                                                   Water                    17                                                   Low Odor Paraffin Solvent                                                                              96                                                   Brij 92                   4                                                   ______________________________________                                    

A 4 gram sample of the above latex is added with stirring to 600 ml ofwater containing 0.4% Triton X-100. The polymer dissolves within 10minutes to give a solution of aminomethylated polyacrylamide.

EXAMPLE 6

A mixture of 287 grams (9.24 moles) of methylamine (755 grams of 37%aqueous solution). 400 grams of Low Odor Paraffin Solvent and 50 gramsof Brij 92 is emulsified by passage through a Manton Gaulin Homogenizer.The emulsion is placed in a 5 liter flask provided with a stirrer,condenser, thermometer, and cooling path, and 850 grams (9 moles) ofepichlorohydrin is added over a 2 hour period at 40°-45° C. Next, 450grams of 50% aqueous NaOH (4.5 moles) is emulsified with 250 grams ofLow Odor Paraffin Solvent and 20 grams of Brij 92 and added over a 1hour period with the temperature held at 70°-80° C. Heating is continuedfor one hour at 60° C. The product is a free flowing, non-viscous liquidthat is readily dissolved in water by use of a water soluble surfactant.

EXAMPLE 7

A 100 gram sample of Nalco 7171 is dried by the same process asdescribed for Example 1, Sample B, and the dried latex particles arecentifuged to remove hydrocarbon and then air dried at 50° C to driveoff the remaining traces of hydrocarbon. The product is a fine whitepowder.

EXAMPLE 8 Self-Dissolving Compositions

The following latices are prepared according to the methods described byVanderhoff, U.S. Pat. No. 3,284,393, and dried to a polymer/water ratioof 90/10 and a polymer to mineral oil ratio (ISOPAR-M of 1:1 by themethod of the present imvention. Surfactant is added to the driedsuspension, after which the mixture is added to stirred water in suchproportions as to give a polymer concentration of 0.4%. The waterthickens almost immediately and reaches maximum viscosity in most caseswithin 20- 40 minutes, which indicates that the polymer has dissolved inthe water.

    ______________________________________                                                                   Weight % of                                                         Surfactant                                                                              Surfactant in                                      Polymer          Identity  Total Composition                                  ______________________________________                                        Acrylamide       (1)       7%                                                 "                (3)       6%                                                 "                (4)       11%                                                Acrylic Acid     (1)       6%                                                 "                (3)       5%                                                 "                (4)       10%                                                Acrylic acid/                                                                 acrylamide 30/70 (1)       6%                                                 "                (3)       5%                                                 Acrylic acid/    (4)       10%                                                acrylamide 30/70                                                              "                (7)       12%                                                "                (8)       4%                                                 Dimethylaminoethyl                                                                             (1)       6%                                                 methacrylate                                                                  "                (2)       6%                                                 "                (3)       5%                                                 "                (6)       10%                                                Sulfomethyl      (1)       6%                                                 acrylamide                                                                    "                (2)       6%                                                 "                (5)       10%                                                Dimethylaminomethyl                                                                            (2)       6%                                                 acrylamide                                                                    "                (3)       6%                                                 "                (6)       10%                                                Methylamine/                                                                  epichlorohydrin 1/1.2                                                                          (2)       6%                                                 "                (3)       6%                                                 "                (6)       10%                                                                           HLB                                                ______________________________________                                        1 POE (10) cetyl ether (Brij 56)                                                                       12.9                                                 2 POE/POP (Pluronic P104)                                                                              13.0                                                 3 POE (12) nonylphenol (Surfonic N120)                                                                 14.1                                                 4 Sodium dioctyl sulfosuccinate (Aerosol-OT)                                                           13.5                                                 5 Ammonium alkyl aromatic                                                                              13.0                                                   sulfonate (Cresterge-K)                                                     6 Tetradecyl trimethyl ammonium chloride                                                               not reported in                                                               literature                                           7 Polyethylene glycol ether of linear alcohol                                                          10.5                                                   (Tergitol 15S5)                                                             8 Polyethylene glycol ether of linear alcohol                                                          10.4                                                   Tergitol 15 S 15                                                            ______________________________________                                    

EXAMPLE 9 Sulfomethylation

A polyacrylamide (PAM) latex is prepared having the followingcomposition:

    ______________________________________                                                                Parts                                                 ______________________________________                                        PAM                       30                                                  Water                     39                                                  Mineral Oil (ISOPAR M)    28                                                  Sorbitan mono-oleate emulsifier                                                                          3                                                  (Span 80)                                                                     ______________________________________                                    

The water is evaporated from this latex at temperatures below 60° C togive a dried product of the following composition:

    ______________________________________                                                    Parts                                                             ______________________________________                                               PAM    30                                                                     Water   3                                                                     Isopar M                                                                             28                                                                     Span 80                                                                               3                                                              ______________________________________                                    

To 65 g of B is added with vigorous stirring in a closed reactor:

(1) 7.5 g of a 40% solution of NaHSO₃ whose pH has been adjusted to 12.0with Na₃ PO₄, and

(2) 1.2g of formaldehyde.

The mixture is then heated with stirring to 50°-55° C and held at thistemperature for 4 hours.

The reaction product is dissolved in water containing 0.04% Tergitol15S9 surfactant (Polyethylene glycol ether of linear alcohol, HLB 13.3)to give a 0.4% solution of polymer. Polymer is precipitated for analysisby adding the aqueous solution to ethanol. The polymer shows a 7 molepercent substitution of sulfomethyl groups.

EXAMPLE 10 Hoffman Reaction

A sample of the latex from part B of Example 2 is dried by vacuumevaporation at temperatures below 80° C to give the followingcomposition:

    ______________________________________                                                          Grams                                                       ______________________________________                                        PAM                 30                                                        Water                3                                                        Isopar M            28                                                        Polyoxyethylene (2) oleate                                                                         4                                                        ______________________________________                                    

a 200 ml round bottom flask is provided with a stirrer, thermometer, gasinlet and outlet. To it is added A, which is then cooled to -20° C.Chlorine is passed in over a one hour period with stirring to give atotal of 0.04 mole of Cl₂. The temperature is raised to 30° C over a twohour period and held at 30° C for another hour. At this time, causticemulsion B is added with vigorous stirring:

    ______________________________________                                                          Grams                                                       ______________________________________                                        Isopar M            10.0                                                      NaOH                3.2                                                       Water               6.0                                                       Polyoxyethylene (2) oleate                                                                        1.0                                                       ______________________________________                                    

Stirring is continued for 30 minutes at 30° C after which the mixture isallowed to stand at 30° for 4 hours. The mixture is then dried to apolymer/water ratio of 95/5 by stripping under vacuum at 30°-45° .Polyoxyethylene (10) cetyl ether (6g) is added to the suspension andmixed in. The product dissolves rapidly in water and analysis ofrecovered polymer shows amino nitrogen.

EXAMPLE 11

A sample of latex prepared as (A) of Example 10 is treated as follows:

To 62 g of A is added 0.045 mole of 3-(dimethylamino) propylamine. Themixture is heated and stirred at 100° C for two hours under vacuum tospeed the release of ammonia.

The product is cooled and a sample is treated with 10 wt % ofpolyoxyethylene (10) cetyl ether. This treated sample dissolves readilyin water to give a 0.4% polymer solution that when added to a diluteslurry of paper fibers makes these fibers strongly cationic.

EXAMPLE 12

An emulsion is prepared having the following composition:

    ______________________________________                                                           %     Grams   Moles                                        ______________________________________                                        Aqueous                                                                              (water            54.6    220                                          phase  (dimethylamine    11.2     45   1                                             (Na.sub.2 CO.sub.3                                                                              34.2    138   1.3                                                             100.0   403                                          Oil    (1,2dibromoethane         187.9 1                                      Phase  (Isopar M                 100                                                 (Brij 92 (Polyoxyethylene (2)                                                 oleyl ether)               5                                                  (Brij 72 (Polyoxyethylene (2)                                                 stearyl ether)             15                                          ______________________________________                                    

The above emulsion is formed by passing the mixture through ahomogenizer at 60° C and from there into a closed reactor provided withagitation, temperature and pressure recording and temperature control.

The emulsion is held at 60° for 8 hours and is then cooled to 50° C anddried under vacuum at 50° to a polymer/water ratio of 95/5. To theproduct is added 10 wt % of polyoxyethylene (10) cetyl ether. Theresultant mixture is a stable suspension that dissolves readily whenadded to water to give a 0.5% solution. The aqueous solution, when addedto a dilute suspension of cellulose pulp, makes the fibers stronglycationic.

EXAMPLE 13

A copolymer latex dried by the method of this patent application andhaving composition A

    ______________________________________                                                                Grams                                                 ______________________________________                                        Solid      (copolymer of acrylamide/                                                                        --                                              Phase      (dimethylaminoethyl                                                           (methacrylate 80/20                                                                              30                                                         (water              3                                              Oil        (Isopar M          20                                              Phase      (Span 80            3                                              ______________________________________                                    

is treated in a closed system under pressure with 4.4 g of methylbromide for a period of 8 hours at 50° C. The reaction mixture is cooledand to it is added 10 wt % of polyoxyethylene (10) cetyl ether. Theresultant mixture dissolves readily in water to give a 0.4% solution ofpolymer that when added to a dilute slurry of cellulose fibers makethese fibers strongly cationic.

EXAMPLE 14

A copolymer latex dried by the method of this patent application andhaving composition A

    ______________________________________                                                                  E                                                   ______________________________________                                        Solid       (copolymer of acrylamide/                                         Phase       (vinyl bromide; 90/10                                                                             30                                                        (water               3                                            Oil         (Isopar M           20                                            Phase       (Span 80             3                                            ______________________________________                                    

is treated in a closed system with 2.7g of trimethylamine at 50° for 8hours. The reaction mixture is cooled and to it is added 10 wt % ofpolyoxyethylene (10) cetyl ether. The resultant mixture dissolvesreadily in water to give a 0.4% solution of polymer that when added to adilute slurry of cellulose fibers makes these fibers strongly cationic.

EXAMPLE 15

A polyacrylamide latex was prepared and vacuum dried to give composition(A) below.

    ______________________________________                                                      %                                                               ______________________________________                                               PAM      22.1                                                                 Moisture 2.0                                                                  Hydrocarbon                                                                            75.0                                                          ______________________________________                                    

to 20 parts of A was added with stirring the following:

    ______________________________________                                                            Parts                                                     ______________________________________                                        Mineral spirits       10                                                      Polyoxyethylene (2) oleyl ether                                                                     2                                                       20% NaOH in Methanol  1                                                       ______________________________________                                    

The resulting mixture was stirred at 30° C for 27 hours, at which timeNH₃ evolution had ceased. Carboxyl content of the resulting polymer was6.6 mole %.

EXAMPLE 16

To 20 parts of composition A of Example 15 was added the following:

    ______________________________________                                                         Parts                                                        ______________________________________                                        Mineral spirits    40                                                         Polyoxyethylene (2) oleyl                                                     ether              8                                                          20% NaOH in Methanol                                                                             4                                                          ______________________________________                                    

The resulting mixture was stirred for 52 hours and heated to 50° C forthe last hour. Carboxyl content of the resulting polymer was 22 mole %.

The present invention is particularly advantageous in that by proceedingin accordance with the invention, it is possible to produce watersoluble polymers dispersed in oil which are stable to coagulation oragglomeration when subjected to subsequent treatment.

In accordance with the present invention, it is possible to provide selfdissolving polymer compositions by addition of a surfactant, to acomposition of water soluble polymer dispersed in oil, without thepolymer agglomeration or coagulation which would occur withoutproceeding in accordance with the invention.

Furthermore, the present invention offers the advantage that variouswater soluble polymers can be chemically modified, without thedisadvantages inherent in attempting to modify such polymers, inparticular, those of high molecular weight, by ordinary techniques.

As still another advantage, amine condensation polymers can be producedwithout limiting the polymer concentrations as heretofore required inthe art.

Numerous modifications and variations of the present invention arepossible in light of the above teachings and, therefore, within thescope of the appended claims, the invention may be practised otherwisethan as particularly described.

What is claimed:
 1. An improved process for chemically modifying a watersoluble polymer selected from the group consisting of acrylamidepolymers and methacrylamide polymers, comprising:chemically modifyingsaid polymer dispersed in oil, without coagulation or agglomeration ofsaid polymer, said dispersion having a water content at which thepolymer remains finely divided and dispersed in the oil, said watercontent being less than 40%, by weight, based on said polymer and water,said polymer dispersed in oil having been prepared from a water in oilemulsion of said polymer by reduction of the water content thereof. 2.The process of claim 1 wherein said chemical modification is selectedfrom the group consisting of hydrolysis of amide to carboxyl,dimethylaminomethylation of amide, sulfomethylation of amide, Hoffmanreaction, and exchange of amide nitrogen for nitrogen ofN,N-dimethylaminopropylamine.
 3. The process of claim 1 wherein saidchemical modification is hydrolysis with gaseous ammonia.
 4. The processof claim 2 wherein said water content is from 1% to 30%, by weight, ofwater, based on polymer and water.
 5. The process of claim 4 whereinsaid water content is from 1 to 15%, by weight, of water, based onpolymer and water.
 6. The process of claim 2 wherein the polymerdispersed in oil is prepared from a water in oil emulsion containingfrom about 50 to about 90%, by weight, water, based on polymer andwater.
 7. The process of claim 2 wherein the polymer has a molecularweight of at least 100,000.
 8. The process of claim 2 wherein thechemical modification is hydrolysis of amide to carboxyl.
 9. The processof claim 2 wherein the chemical modification is dimethylaminomethylationof amide.
 10. The process of claim 2 wherein the chemical modificationis sulfomethylation of amide.
 11. The process of claim 2 wherein thechemical modification is Hoffman reaction.
 12. The process of claim 2wherein the chemical modification is exchange of amide nitrogen fornitrogen of N,N-dimethylaminopropylamine.